Oil Leak Pic - Can you guess where it is coming from Plus what is this on the window?

I have attached four pics - first two of my constant oil drip - assume it's the lowest point on the jeep but can anyone give me an idea of where it may be coming from? If you look close you can see a drip in the middle forming.

The next two pictures are from the back window on passanger side. Does anyone know what this is or used for? Old CB? Temp Gauge? Ect.

Has anyone replaced the rear seal?
Is it something I could do being new to vehicles?
Do I need to lift the jeep or can I do it with the clearance?
If I take it somewhere what do you think someone should charge for that?

To replace it you need to either pull the engine or the tranny. A lift with a tranny jack would be much more convenient. Then run two self tapping screws in and pull on them until it comes out. Then grease the new one and knock it in with the flat side of a block of wood so it goes in evenly.

The rear main can be replaced without pulling the engine or the trans. Just the pan has to come off and the main bearing caps loosened.

It's not a job for someone with little to no auto repair experience, however.

There's no guarantee that's where the leak is coming from either. It could be as simple as a valve cover gasket leak.

x2 on that item on the back window being a cell phone antenna base. Double stick tape holds them on.

I agree had the rear main seal changed in my 360 you have to go in through the oil pan. Guy charged me around $160 or so to change it, and I still have a leak from somewhere. If you're not losing massive amounts of oil, I wouldn't bother with it. You can spend a whole lot of money and half your life chasing down a small oil leak. Oh and thats definitely some sort of antenna mount.